<?php

    //获得参数 signature nonce token timestamp echostr
    $nonce     = $_GET['nonce'];
    $token     = 'token';
    $timestamp = $_GET['timestamp'];
    $echostr   = $_GET['echostr'];
    $signature = $_GET['signature'];
    //形成数组，然后按字典序排序
    $array = array();
    $array = array($nonce, $timestamp, $token);
    sort($array);
    //拼接成字符串,sha1加密 ，然后与signature进行校验
    $str = sha1( implode( $array ) );
    if( $str  == $signature && $echostr ){
        //第一次接入weixin api接口的时候
        echo  $echostr;
        exit;
    }
